1. Field of the Invention
This invention relates to a bearing assembly for allowing a relative linear motion between two elements theoretically for an indefinite length, and, in particular, to a linear motion rolling contact bearing assembly suitable for use in high-precision apparatuses, such as NC machining tools, robots, information and office automation equipment.
2. Description of the Prior Art
A linear motion rolling contact bearing assembly is known in the art and it includes a rail extending straight over a desired length, a slider slidably mounted on the rail and a plurality of rolling members interposed between the rail and the slider, thereby providing a rolling contact between the rail and the slider. Such a linear motion rolling contact bearing assembly may be applied to various equipment and machines whenever a relative linear motion between two elements is required. In general, such a linear motion rolling contact bearing assembly is preferably compact in side. Thus, use is typically made of a thin steel plate for forming the rail and/or slider, at least partly. In this case, because of the reduced rigidity of a thin steel plate, it is often difficult to obtain true straightness for the rail and/or slider, which then constitutes an obstacle for wide application of such a linear motion rolling contact bearing assembly.
For example, in the past, such a linear motion rolling contact bearing assembly was often used in such devices as cabinets and desk drawers, which do not require close tolerances. However, partly due to the recent dissemination of various advanced office automation equipment, such as office computers, word processors, and copiers, as well as robots, and machining tools, there has arisen a need to develop a novel linear motion rolling contact bearing assembly high in precision, light in weight, and small in size. In particular, since such a linear motion rolling contact bearing assembly is mounted in an apparatus when used, it is critical that error or distortion produced due to such mounting is minimized or preferably non-existent.